Telephone-transmitter.



H. P. OLAUSEN.

TELEPHONE TRANSMITTER.

APPLIOATION rmm mus. 1004.

Patented Mar. 2, 1909.

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Patented Mar. 2, 1909.

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H. P. GLAUSEN. TELEPHONE TRANSMITTER.

I APPLIOATIOH TILED JULY 9. 1904. 91 3.944. Patented Mar. 2, 1909.

3 SHEETS-SHEET 3.

i m N UNIT STATE PATENT FFC.

HENRY P. OLAUSEN, OF CHICAGO, ILLINOIS, ASSIGNOR lO THE AMERICAN ELECTRIC TELEPHONE COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION.

TELEPHONE-TRANSMITTER.

Specification of Letters Patent.

Patented March 2, 1909.

Application filed July 9, 1904. Serial No. 215,951.

To all whom it may concern:

Be it known that I, HENRY P. CLAUSEN, a citizen of the United States of America, and resident of Chicago, Cook county, Illinois, have invented a certain new and useful Improvement in Telephone-Transmitters, of which the following is a specification.

My invention relates to that form of transmitter in which the diaphragm is connected with a bridge or other member through the medium of a box or closure containing the electrodes and interposed granular carbon and having resilient front and back walls adapted to permit the vibrations of the diaphragm to produce the desired or necessary relative movement between the two electrodes for the purpose of varying the resilience in the manner characteristic of microphone transmitters of this particular type.

Generally stated, the object of my invention is the provision of a simple, improved and highly efficient microphone of the foregoing character.

A special object is to provide an improved construction and arrangement of the box containing the electrodes and granular carbon, whereby the granular carbon, although effectually insulated from the structure of the box, will have no tendency to become wedged in between the springy or resilient walls of the box and the backs of the adjacent electrodes.

Another object is to provide an improved construction and arrangement involving one or more springy or resilient auxiliary diaphragms held normally under stress or tension, whereby the transmitter is made more sensitive and eflicient with respect to the transmission of speech.

It is also an object to provide certain details and features of improvement tending to increase the general efficiency and serviceability of a telephone transmitter of this particular character.

To the foregoing and other useful ends, my invention consists in matters hereinafter set forth and claimed.

In the accompanying drawings, Figure 1 is a sectional view of a transmitter embodying the principles of my invention, the sheet metal box containing the electrodes and granular carbon being shown in side elevation. Fig. 2 is an enlarged longitudinal section of the said box or closure, containing the electrodes and granular carbon. Fig. 3 is a rear end view, on a somewhat reduced scale, of a transmitter with the casing removed. Fig. i is a view on the same scale as, and similar to, Fig. 2, but showing the difl'erent parts separated and ready for assembling. Figs. 5 and 6 are diagrammatic views illustrating different methods of placing the auxiliary diaphragms under stress or tension.

As thus illustrated, my improved microphone transmitter comprises a body A, preferably of metal, provided centrally with an opening, and a mouthpiece B composed of insulation and screwed into the said opening. The main diaphragm C has its periphery or mar inal portion provided with a rubber band 0, which is stretched around the diaphragm in such manner as to lie flat upon its opposite surfaces. The said diaphragm is preferably held in place in said body A by means of spring lingers D, as shown more clearly in Fig. 3; it being observed that these spring fingers are provided at their ends with pieces of rubber or other insulation (1, whereby the said diaphragm has no electrical connection whatever with the frame or body of the transmitter.

The box E contains the electrodes and granular carbon. as shown in Fig. 2, and constitutes the medium of resilient and yielding connection between the said diaphragm and the bridge F. As illustrated, the front electrode G consists of a disk of carbon secured in any suitable manner to a disk of metal, said metal disk having its back provided with a threaded stem g, and with a shoulder 9. Also, as shown, the back electrode H is composed of a disk of carbon secured to a disk of metal, said metal disk having its back provided with a threaded stem h, and also with a shoulder 71/. When adjusted in place, as shown in Fig. 1, the diaphragm O is clamped between a nut g screwed on to the outer end of the stem g, and the nut 9 the latter being screwed on to the stem to clamp the front auxiliary diaphragm 6 against the shoulder g. It will also be observed, at this juncture, that a metal terminal g" is preferably interposed between the diaphragm and the said nut g In this way, the nut g clamps the auxiliary diaphragm e firmly to the front l electrode, while the nut g clamps the front by the said set-screwf.

electrode firmly to the main diaphragm C. In a similar manner, a nut 7L2 clamps the back electrode firmly to the rear auxiliary diaphragm e and in this case, it is also desirable to interpose a metal terminal h between the said nut and the said auxiliary diaphragm.

It will be seen that the bridge F is provided centrally with a hub-portion f, and this hub-portion is provided with a set-screwf, as shown more clearly in Fig. A. cylindrical lock-nut I, having its forward end threaded and screwed on to the stem h, is adapted to fit the bore of the hub f, and to be retained therein in any desired position It will be observed that the said lock-nut is preferably composed of inner and outer metal cylinders t and t, and an interposed cylinder of insulation i. In this Way, the back electrode H is clamped firmly to the bridge without establishing any electrical connection therewith.

Insulated binding posts J and K can be mounted on the bridge and connected respectively with the metal terminals 9 and 72/ as shown more clearly in Fig. 1. With this arrangement the binding post J is electrically connected with the front electrode, while the binding post K is electrically connected with the back electrode. The front electrode is, of course, adapted to vibrate with the main diaphragm (l, but the back electrode is held stationary; and with respect to this feature. it will be seen that the two auxiliary diaphragms constitute a medium of springy or resilient connection between the two electrodes, and, consequently, between the main diaphragm and the bridge.

Referring to Figs. 2 and l, it will be seen that the sheet metal box E, having the said front and back auxiliary diaphragms, is constructed in a very simple and highly eflicient manner. The two auxiliary diaphragms are, it will be seen, cup-shaped and provided with peripheral flanges e and c and these auxiliary diaphragms are also provided with central apertures to accommodate the threaded stems on the backs of the electrodes. The said flanges, together with the cylindric portions c and e of the two auxiliary diaphragms, constitute medium of rigid or nonyielding connection between the two auxiliary diaphragms; and this is accomplished by clamping the two flanges together by means of a band of sheet metal 6. Tris band of sheet metal, when applied, is pressed into the form shown in Fig. 2, whereby it is adapted to serve as a clamping ring to clamp the two diaphragms together, and effectually preferably hermetically,seal the inclosure thus provided for containing the electrodes and granular carbon.

As illustrated, a ring or washer of felt e is interposed between the flanges of the two auxiliary diaphragms; but it is obvious that any other suitable insulating or similar material may be employed for this purpose.

xlSO, as illustrated, flat rings or washers e and e are interposed between the clamping ring 6 and the outer surfaces of the flanges on the auxiliary diaphragms, these rings being preferably of mica or similar material. In addition, the granular carbon Within. the box is insulated therefrom by means of bands of paper 6 and 6 having peripheral flanges 6 6 adapted to be interposed between the ring 0 and the inner surfaces of the flanges on the auxiliary diaphragms. Furthermore, flat apertured disks e and e of felt or similar material are interposed between. the auxiliary diaphragms and the backs of the metal disks upon which the carbon disks of the electrodes are mounted. Finally, the insulation of the granular carbon from the structure of the box is completed by the provision of rings of felt e and e which encircle the two electrodes and are of suflicient thickness to extend slightly over the edges of the carbon disks. in this way, the metal bodies of the two electrodes are clamped directly and firmly against the central por tions of the two auxiliary metal diaphragms. The flat disks and rings associated with the two electrodes effectually insulate the granular carbon from the sheet metal box, and at the same time permit the necessary spring or relative movement on the part of the auxiliary diaphragms without danger of allowing the carbon granules to become wedged in or crowded between the electrodes and the auxiliary diaphragms. Consequently, and with the provision of insulation between the flanges of the auxiliary diaphragms, the sheet metal box composed of the two diaphragms is not included in the electrical circuit of the instrument.

With an instrument of this character, I find that the sensitiveness thereof, and the elliciency with respect to transmission of speech, is increased by normally maintaining the two auxiliary diaphragms, or either one of them, under more or less stress or tension. In other words, should the locknut I be adjusted toward the main diaphragm to an extent to slightly compress the sheet metal box, thereby dishing the two auxiliary diaphragms in the manner shown in Fig. 5, improved transmission is thereby obtained. The two auxiliary diaphragms can be retained in the condition shown in Fig. 5, by simply pushing the lock-nut I toward the main diaphragm, as stated, and by then securing the same in place by the set-screw f.

Still another way of placing the auxiliary diaphragms under stress or tension consists in so tensioning the spring fingers D as to bulge the main diaphragm in the manner shown in Fig. 6. l Vhen thus acted on by the spring fingers, the main diaphragm tends to pull the box E forward, and in so doing cause the two auxiliary diaphragms to bulge outwardly, as shown in Fig. 6. But in either case, it will be seen that the two auxiliary diaphragms are given a normal stress or tensionsufficient to give the desired results that is to say, sufficient to more or less improve the transmission. I find that only a very slight flexing of the two auxiliary diaphragms from their normal or flat condition is necessary to accomplish this result; and if the method employed in Fig. 5 is shown, the main dia hragm would probably not be placed under as much tension as would be the case if the method shown in Fig. 6 were employed; and this is due, it will be seen, to the fact that the main diaphragm is preferably of somewhat heavier or thicker material than the auxiliary diaphragms.

Thus, it will be seen that I provide an improved and highly efficient telephone transmitter involving an improved construction of the box for containing the granular carbon, and electrodes, and involving also the feature of one or more auxiliary dia hragms normally under stress or tension, wl iich feature is, I find, as previously explained, calculated to improve the transmission.

It will be observed that the cylinder i preferably has a polygonal here which per mits the nut to be turned by a suitable tool.

Prior to. my invention, it has always been the custom in practice to carefully adjust the carbon chamber or box of a microphone transmitter, for the purpose of permitting the auxiliary diaphragm thereof to remain normally Without stress or tension-that is to say, in a flattened condition. In other words, it has heretofore always been considered that any normal stress or flexing or tension on the part of an auxiliary diaphragm, in a transmitter of this kind, would be injurious and undesirable, and consequently precautions were always taken with a view to seeing that the auxiliary diaphragms were absolutely free of stress or tension before the transmitters'went into use. I have discovered, however, as I have explained, that substantial stress or tension on the part of the auxiliary diaphragm is really a beneficial expedient, and that a transmitter constructed on this plan is highly efficient, and not subject to some of the troubles and disadvantages of those heretofore employed. Throughout the foregoing, as well as in the following claims, it will be understood, therefore, that by an auxiliary diaphragm which is normally under stress or tension, I mean an auxiliary dia hragm which is normally flexed and held unr er tension to a definite and useful degree, so as to render the structure more stable and accurate in the transmission of speech, as distinguished from an auxiliary diaphragm having a mere incidental or indefinite degree of tension, such as would not be (and has never been) recognized as being of any advantage or utility in a telephone transmitter of this character. It is true, of course, that prior to my invention some transmitters may have been accidentally so adjusted as to give the auxiliary diaphragm an inappreciablo stress or tension while in its normal position. But even so, such tension or stress (if it ever existed) was never recognized as being of any valuein fact, every effort was made to avoid such stress or tension. I am, therefore, the first to give the auxiliary diaphragm a definite, positive and well defined normal stress or tension by materially flexing it in one direction or the other, and the first to establish the practice of definitely and posi tively tensioning the auxiliary diaphragm before the transmitter is put in use. I find that in the installation of a telephone system, the transmitters give better results when the auxiliary diaphragms thereof are given a definite and well defined degree of stress or tension, than when the same are installed without tension. It is better, I find, to uniformly tension the auxiliary diaphragms of the different transmitters, than it is to pursue the old practice of carefully adjusting them without tension. As I say, therefore, I am the first to reverse the old practice in this respect, and establish the new practice of giving the auxiliary diaphragms a uniform and positive and well defined normal stress or tension.

What I claim as my invention is:

1. A telephone transmitter comprising a main diaphragm, a bridge, a vibratory front electrode connectrd with the said main diaphragm, a stationary back electrode connected with the said bridge, granular carbon between the two electrodes, resilient front and back auxiliary diaphragms of metal clamped respectively to said front and back electrodes, insulation between the auxiliary diaphragms, and insulation between the granular carbon and the said auxiliary diaphragms, and a circuit including said electrodes, but excluding the metal auxiliary diaphragms as a necessary portion thereof, each auxiliary diaphragm having metallic contact with its associated electrode.

2. A telephone transmitter comprising a main diaphragm, a vibratory front electrode connected with the main diaphragm, a stationary back electrode, granular carbon between the two electrodcs, resilient front and back auxiliary diaphragms of metal clamped respectively to said front and back electrodes, disks of insulation interposed between the backs of said electrodes and the adjacent surfaces of said auxiliary diaphragms, and rings of insulation encircling said electrodes, and a circuit including said electrodes, but excluding the metal auxiliary diaphragms as a necessary portion thereof, each auxiliary diaphragm having metallic contact with its associated electrode.

3. A telephone transmitter comprising a mam diaphragm, a vibratory front electrode connected with the said mam diaphragm, a

.stationary back electrode, granular carbon between said electrodes, resilient metallic front and back auxiliary diaphragms clamped respectively to said front and back elc ctrodes, insulation between said auxiliary diaphragms, and insulation between the granu lar carbon and said auxiliary diaphragms, and a circuit including said electrodes, but excluding the metal auxiliary diaphragms as a necessary portion thereof, each auxiliary diaphragm having metallic contact with its associated electrode.

i. A telephone transmitter comprising a main diaphragm, a vibratory front electrode connected with said main diaphragm, a stationary back electrode, granular carbon be tween said electrodes, a pair of sheet metal cups inclosing said electrodes and carbon, each cup having its middle portion clamped to the back of one of said electrodes, insulation interposed between the perimeter of said cups, a clamping ring for securing said cups together at their perimeters, and insulation between the granular carbon and said cups, and a circuit including said electrodes, but excluding said cups as a necessary portion thereof each cup having metallic contact with its associated electrode.

5. A telephone transmitter comprising a main diaphragm, front and back electrodes, an auxiliary diaphragm, a bridge, said auxiliarydiaphragm constituting medium of resilient connection between the main diaphragm and the said bridge, a cylindric nut screwed upon the back electrode, and means for adjustably securing said nut to said bridge said nut being adjustable and removableby manipulation thereof at the rear of the bridge.

6. A telephone transmitter comprising a main diaphragm, a bridge, a vibratory electrode connected with the said main diaphragm a cylindric nut adjustably secured to said bridge, a stationary electrode having a portion thereof screwed into said nut, resilient front and back auxiliary diaphragms clamped respectively to said front and back electrodes, and granular carbon interposed between said electrodes, said auxiliary diaphragms constituting medium of yielding resilient connection between the main diaphragm and the bridge.

'7. A telephone transmitter comprisnig a main diaphragm, bridge, a vibratory front electrode having a stem extending through and clamped to the main diaphragm, a cylindric nut adiustably secured to the bridge, a stationary back electrode having a portion thereof screwed into said nut, said nut being provided with means for insulating the back electrode from the bridge, granular carbon between the two electrodes, and a eiaeaa sheet metal box inclosing said electrodes and granular carbon, said sheet metal box having front and back walls constituting medium of yielding connection between the bridge and the main diaphragm, and said box being composed of two parts insulated from each other.

8. A telephone transmitter comprising a main diaphragm, vibratory front electrode connected with the saidmain diaphragm, a bridge, a stationary back electrode connected with said bridge, granular carbon be tween the two electrodes, and a sheet metal box inclosin said electrodes and granular carbon, said box having front and back walls constituting medium of yielding resilient connection between the main diaphragm and the bridge, and said box being composed of two parts insulated from each other, and a circuit includin said electrodes, but excluding said box as a necessary portion thereof each part in direct metallic contact with its associated electrode.

9. A telephone transmitter comprising a main diaphragm, relatively vibrating elec trodes, means for holding one electrode stationary, granular carbon between the electrodes, a bridge, and an auxiliary diaphragm having its central portion rigidly connected with the central portion of the main diaphragm, said auxiliary diaphragm being normally under stress or tension and constituting medium of yielding or resilient connection between the main diaphragm and the bridge whereby said main diaphragm is also normally under stress or tension.

10. A telephone transmitter comprising a main diaphragm, a stationary member, a vibratory electrode connected with the main diaphragm, a stationary electrode connected with the said stationary member, granular carbon between the two electrodes, means for setting the stationary electrode forward or back to variously tension the main diaphragm, and an auxiliary diaphragm normally under stress or tension and constituting medium of yielding connection between the said main diaphragm and stationary member together with a rigid connection between the stationary member and the central portion of the said auxiliary diaphragm, whereby sair main diaphragm is also normally under stress or tension.

11. A telephone transmitter comprising a main diaphragm, a stationary member, a vibratory electrode connected with the said main diaphragm, a stationary electrode connected with the said member, means for setting the stationary electrode forward or back to variously tension the main diaphragm, granular carbon between the two electrodes, and resilient front and back auxiliary diaphragms, said auxiliary diaphragms being normally under stress or tension and constituting medium of yielding connection be- I p the diaphragm and bridge, and a cylindric nut screwed upon the said stem and adjustably clamped in the bridge, together with one or more auxiliary diaphragms connecting the said stem and diaphragm, said nut havin a poli gonal bore, said nut being adjustable an removable by manipulation thereof at the rearof the bridge.

13. In a telephone transmitter, the combination of a main diaphragm, an auxiliary diaphragm, both diaphragms normally under stress or tension, and stationary means for preserving and opposing the tension of said diaphragms.

14. A telephone transmitter provided with main and auxiliary diaphragms, the latter normally flexed and under tension, as set forth.

15. A telephone transmitter provided 1,.

with main and auxiliary diaphragms, the latter normally flexed and held under tension by the spring pressure or pull of the former, as set forth.

16. In a telephone transmitter, a vibrating electrode, a relatively stationary electrode, a chamber containing said electrodes, a flexible wall adjacent to said stationary electrode forming a closure for said chamber, and means imparting a normal stress to said wall.

Signed by me at Chicago, Cook county, Illinois, this 29th day of June 1904.

HENRY P. CLAUSE. Witnesses:

CLARENCE M. THORNE, MA'rTrE B. BLrss. 

